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Behaviorally Modern Humans: The Origin of Us

Current evidence indicates that multiple upright-walking, tool-dependent species in the genus Homo co-existed in the Old World (Africa, Asia and Europe) for most of the last 2 million years. Yet only one surviving species of Homo exists today. Even 100,000 years ago, at least four Homo species shared the Old World. One of the enduring questions of human origins is when, where and how we "Behaviorally Modern Humans" emerged and why and how we eventually replaced all the other human-like species. In the past, competing theories have generated much controversy and even some acrimonious debate. This symposium set aside such theories and debates and took a fresh look at the situation today. The focus was on critical examination of the available evidence from multiple sources, including climate proxies, geology, fossils, archaeology, linguistics, immunology, genetics and genomics, as well as evolutionary neuroscience/cognitive archaeology. While the symposium may not have come to any definitive conclusions, it offered the best interpretation of current evidence, and suggested research agendas for the future. (from carta.anthropogeny.org)

1. African Climate of the Last 400,000 Years
Rick Potts suggests that the complexity of climate dynamics, and associated resource uncertainty, likely influenced the evolution of adaptive versatility in our species.

2. Fossil Record of Anatomically Modern Humans
Evidence points strongly to Africa as the major center for the genetic, physical and behavioral origins of both ancient and modern humans.

3. East African Archaeological Evidence
Apart from references to the oldest fossil hominins attributed to Homo sapiens, the East African record is often ignored in current scenarios of modern human origins in favor of the much more detailed, well-preserved and better-explored region at the southern end of the continent.

4. South African Archaeological Evidence
Lyn Wadley contends that the manufacture of compound adhesives and compound paints by 100,000 years ago in South Africa is clear evidence for modern thought processes that involve, for example, multi-tasking.

5. Interbreeding with Archaic Humans in Africa
Today there is an abundance of DNA sequence data from the entire genome of contemporary human populations, as well as from ancient DNA recovered from extinct forms of humans.

6. Relationships of Ancient African Languages
Almost all of the more than 1,000 African languages spoken today belong to just four families Afroasiatic, Niger-Kordofanian, Nilo-Saharan, and Khoesan.

7. Evidence for the Spread of Modern Humans
Ofer Bar-Yosef briefly summarizes the archaeological evidence for the dispersals of modern humans into Eurasia.

8. Interbreeding with Archaic Humans Outside Africa
Neanderthals and Denisovans are the closest extinct ancestors of modern humans. High-quality genome sequence data is now available from both and has revealed multiple instances of admixture between these archaic hominins and the ancestors of currently living humans.

9. Stone Tools and Cognition: Lessons from Australia
What is cognition? Can we learn anything from brains? What was the cognitive ability of the Last Common Ancestor? And, how can we learn from stone tools?